The Morse Taper Drill Sleeves are hardened steel, internally and externally ground. Size adaptors from one size stepping up to the next or skipping to a couple larger sizes (ie; 2- MT sleeve); this allows a No.2 Morse taper drill to be sleeved to suit a No.3 Morse taper machine spindle. Quite often several Drill Sleeves are joined together to gain the required Morse taper. Morse tapers range from No.0 Morse taper up to No.7 Morse taper. No.3 is the most popular; drills aprox. 23mm thru to 32mm. Most bench drill presses are either No.2 or No.3 Morse taper spindles. Morse taper sleeves are also available as an extension arbor whereby you can extend the length of a cutting tool using a 3MT - 3MT extension sleeve (aprox. 200mm in length).